How can I tell whether my preschooler has food poisoning?

Food poisoning, which is usually caused by eating food or drinking water that's contaminated with one of several kinds of nasty bacteria, can be hard to distinguish from a stomach virus, which is usually picked up on the hands and transferred to the mouth. The symptoms are the same: abdominal cramping, nausea, vomiting, diarrhea, and often fever, chills, achiness, and headache.

If your preschooler has food poisoning, the symptoms will likely appear two to 48 hours after eating the food and will usually last a day or two but can continue in severe cases for a week or more.

How can I tell what kind of food poisoning my child has?

Testing of blood, stool, and leftover food may identify the bacteria when necessary, but often the doctor won't need to identify the exact culprit because the treatment is the same regardless. (In fact, the treatment is the same for a stomach virus, too.) There are exceptions, though. If there's blood in your toddler's stool, for example, the doctor will test to make sure that he doesn't have food poisoning that's caused by a potentially dangerous bacteria, like E. coli 0157:H7, Shigella, or Salmonella.

According to the Centers for Disease Control and Prevention (CDC), the most common food-borne infections are those caused by the bacteria Campylobacter, Salmonella, and E. coli 0157:H7, as well as by a group of viruses called noroviruses. Less common – but dangerous if left untreated – is botulism. Here's a quick look at these bacteria:

Campylobacter is the most frequently diagnosed food-borne bacterium. It's usually transmitted through raw or undercooked poultry or unpasteurized milk, but your child can also get it from contaminated water. It's not usually spread from person to person, but it can be. (If your child has it and has diarrhea, for example, you could possibly get it from cleaning him up.)

It's also possible to contract the bacteria from the stool of a dog or cat. Campylobacter often goes undiagnosed because there are sometimes no symptoms, but signs can include nausea and vomiting, diarrhea (sometimes bloody), cramping, abdominal pain, and fever. It usually lasts for two to five days, but can linger for up to ten days.

Salmonella can be present in raw or undercooked eggs, poultry and meat, raw milk and dairy products, and seafood, and can be spread by food handlers. Reptiles like pet iguanas, turtles, lizards, and snakes can also carry Salmonella. In most cases, if your child has a bout of Salmonella, he'll develop fever, diarrhea, and abdominal cramps. He may also have tiny pink spots on his skin.

Symptoms usually start eight to 48 hours after contact and last for a day or two, though they can persist for more than a week, and the bacteria can continue to exist in the body for months. Two-thirds of patients with Salmonella are under 20 years old. In a person with a compromised immune system, Salmonella can invade the bloodstream and become life threatening.

E. coli is transmitted through food or water that's contaminated with microscopic amounts of cow feces. (If a person has E. coli and doesn't wash her hands after using the toilet, she can also spread it to another person.) E. coli can cause severe, sometimes bloody diarrhea and painful abdominal cramps, without much of a fever.

There are a number of strains of Escherichia coli. E. coli 0157:H7 is a particular strain that causes a more severe, longer-lasting illness. In babies and young children, E. coli 0157:H7 can be life threatening and often requires hospitalization. Symptoms can begin eight to 48 hours after your child eats a food contaminated with the bacteria and last about two to five days.

Norovirus is also called Norwalk-like virus (NLVs) or calicivirus, because it belongs to the Caliciviridae virus family. This very common virus isn't often diagnosed because a lab test for it isn't widely available. Severe vomiting is the hallmark sign, and it usually begins suddenly, about 24 to 48 hours after contact with the virus, although symptoms can show up as early as 12 hours.

A norovirus is transmitted through contaminated food, utensils, and surfaces. Because it's highly contagious, it spreads easily in daycare facilities and homes. There are many strains of norovirus, so it's hard to develop immunity to them. A case of norovirus usually goes away on its own in one to two days, but in the meantime you'll want to make sure that your child doesn't get dehydrated because of the vomiting.

Botulism is fairly rare – there are only about 110 cases in the United States each year. It's caused by the bacteria Clostridium botulinum, which is found in soil. But it's most often transmitted through improperly canned or preserved food, especially home-canned vegetables, cured pork and ham, smoked or raw fish, honey, and corn syrup.

Infant botulism happens when a baby eats the bacteria or its spores, and they then grow in his intestinal tract. (This is why you should never feed honey to a baby before his first birthday.) Symptoms of botulism include constipation, weakness, droopy eyelids, and difficulty swallowing. (The child will be alert, though, despite his weakness.) Left untreated, botulism can progress to muscle and respiratory paralysis. The symptoms usually show up in eight to 36 hours.

When should I call the doctor?

You'll want to let the doctor know what's going on as soon as you suspect your child might have food poisoning. She can decide if your child's symptoms warrant an office visit. Tell the doctor about any of the following signs:

a fever higher than 103 degrees Fahrenheit

vomiting for more than three days

severe headaches or abdominal pain

blood in the stool or vomit

a swollen, hard belly

Also call your doctor if your child shows any of the classic signs of dehydration, including decreased urination, excessive sleepiness or fussiness, cool and discolored hands and feet, or extreme thirst. If this happens, your child's doctor might want to admit him to the hospital (or just keep him there for a few hours) for IV rehydration. Don't be alarmed. Odds are, he'll be released and back to his healthy self within a few days' time.

If you're concerned that your child may have food poisoning and your doctor isn't available, speak to the doctor on call or take your child to the emergency room.

If your preschooler is having trouble breathing or swallowing, or shows any signs of severe dehydration, call 911.

What can I do to ease my child's symptoms?

Assuming your child has a run-of-the-mill case of food poisoning, with vomiting or diarrhea, you'll want to keep him home to rest and replace the lost fluids and electrolytes (salt and minerals) that his body is losing. Usually, doctors recommend giving an over-the-counter oral electrolyte solution, such as Equalyte or Pedialyte (which is also sold as ice pops), by offering small sips frequently throughout the day. Your doctor can tell you how much your child needs to be drinking based on his age and weight. (Avoid juices and sodas, though, because these may make his symptoms worse.)

If your child has a fever or is achy, you can give him the proper dose of children's acetaminophen or ibuprofen. Never give your child aspirin as it makes him more susceptible to Reye's syndrome, a rare but potentially fatal disease.

When can my child go back to eating normally?

Once your child's vomiting and diarrhea lessens or stops, and his appetite returns, your doctor will likely recommend that you stop giving him the electrolyte solution as you slowly reintroduce other fluids, including milk, as well as healthful food. Follow your child's cues – he'll let you know when he feels hungry.

The American Academy of Pediatrics (AAP) recommends that children recovering from stomach troubles resume a normal diet as soon as possible – one that includes such staples as complex carbohydrates (like bread, cereal, and rice), lean meat, yogurt, fruits, and vegetables. Avoid fatty food.

Note that this recommendation is different from the BRAT diet (bananas, rice, applesauce, and toast) that doctors used to prescribe. "The BRAT diet used to be very commonly advocated, but we no longer recommend it because it lacks certain vital nutrients, such as protein," says William John Cochran, an associate professor of pediatrics at the Geisinger Clinic in Danville, Pennsylvania.

Studies show that reintroducing a standard diet soon after acute symptoms ease can actually shorten the duration of a child's illness by half a day because it restores essential nutrients to his system necessary to fight infection. On the other hand, if your child misses a few days' worth of good nutrition because his illness just kills his appetite, don't worry. Just make sure you keep him hydrated.

How can I help protect my child from contracting food-borne illness again?

The truth is, it's impossible to protect your child from all food-borne bacteria. But you can certainly help decrease his odds of exposure by using proper food preparation practices at home. Try these:

Always wash your hands with warm water and soap before preparing food or after going to the bathroom or helping your child with the potty or changing a diaper. Teach your child to wash his hands after he uses the potty and before he eats. Help him until he can do a good job on his own.

Rinse meat, poultry, and fish thoroughly before cooking it, and wash all kitchen surfaces well afterward with hot, sudsy water.

Never put cooked food, like a steak, back on a plate or cutting board that held uncooked food.

Defrost food in the refrigerator, not on the countertop or in the sink. Don't eat meat, poultry, or fish that has been refrigerated uncooked for more than one or two days.

Don't use food that looks or smells unusual.

Don't use outdated food, packaged food that has a broken seal, or cans that are dented or misshapen.

Don't leave food outside the refrigerator for more than an hour before eating or drinking it.

Make sure food is cooked well. Use a meat thermometer: Beef should be at least 160 degrees F, poultry at least 180 degrees F, and fish at least 140 degrees F.

When reheating food, be sure to do so thoroughly. (Don't just warm it.)

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